In animals and plants, innate immunity is regulated by nucleotide binding domain and leucine-rich repeat (NB-LRR) proteins that mediate pathogen recognition and that activate host-cell defense responses [1, 2]. Plant NB-LRR proteins, referred to as R proteins, have amino-terminal domains that contain a coiled coil (CC) or that share similarity with animal Toll and interleukin 1 receptors (TIR) . To investigate R protein function, we are using the TIR-NB-LRR protein N that mediates resistance against tobacco mosaic virus (TMV)  through recognition of the TMV p50 protein. Here, we describe N requirement gene 1 (NRG1), a novel N-resistance component that was identified by a virus-induced gene silencing (VIGS) screen of a cDNA library . Surprisingly, NRG1 encodes an NB-LRR type R protein that, in contrast to N, contains a CC rather than a TIR domain. Our findings support emerging evidence that many disease-resistance pathways each recruit more than a single NB-LRR protein. The results also indicate that, in addition to the previously recognized role in elicitor recognition, NB-LRR proteins may also function in downstream signaling pathways. ©2005 Elsevier Ltd All rights reserved.
Publication Source (Journal or Book title)
Peart, J., Mestre, P., Lu, R., Malcuit, I., & Baulcombe, D. (2005). NRG1, a CC-NB-LRR protein, together with N, a TIR-NB-LRR protein, mediates resistance against tobacco mosaic virus. Current Biology, 15 (10), 968-973. https://doi.org/10.1016/j.cub.2005.04.053